The invention relates to a control arrangement for an internal combustion engine including pressure generating and pressure limiting elements and also control elements and further valves which are arranged in an engine cylinder head and of which at least one is connected to the electronic control arrangement and capable of establishing communication between a combustion chamber and the engine exhaust system.
MTZ, Motortechnishe Zeitschrift 56(1995) 7/8 discloses a control arrangement for an internal combustion engine whereby the engine braking power can be increased during engine braking operation. The control arrangement relates to a so-called decompression valve motorbrake (DVB) or, respectively, DVB-system. The DVB system controls the DVB valves arranged in the cylinder head of the internal combustion engine in such a way that they are no longer kept open during the whole compression stroke of the respective pistons but are opened only shortly before the piston reaches the top dead center position of the compression stroke, that is, compression TDC up to about 90.degree. to 120.degree. crank angle thereafter. In this way, a greater engine braking power can be achieved and compressed air can be discharged from the combustion chamber. The DVB system includes as pressure generating element, a radial piston pump and several pressure limiting elements such as a variable pressure control valve, an excess pressure valve and a return flow throttle. Furthermore, in the DVB system, the radial piston pump is connected, by way of a control line, with a central disc or respectively, a distribution unit by way of which the DVB valves of the various cylinders can be accurately controlled during operation of the internal combustion engine.
However, with the control arrangement described only motor braking operation of an internal combustion engine is possible.
U.S. Pat. No. 5,404,852 discloses an arrangement for controlling air compressed by a piston in a cylinder of an internal combustion engine by means of a control valve. The control valve is adjustable by an electronic control unit during the compression stroke of the piston during different positions before the top dead center position so as to be open or closed. The air withdrawn from the cylinder by way of the control valve is supplied to an exhaust gas pipe. Downstream of the control valve, there is a switch-over valve, by which the compressed air can be supplied selectively to a pressurized air line leading to a pressurized air storage container or to the exhaust pipe when the pressure of the air in the pressurized air storage container has reached a predetermined operating pressure.
In this arrangement, however, the internal combustion engine can be operated as an air compressor only during motor braking operation for generating compressed air for any pressurized air operated systems of a motor vehicle.
It is therefore the object of the present invention to provide an internal combustion engine with a control arrangement by which the internal combustion engine can provide pressurized air under any engine operating condition with little expense by appropriately controlling the engine.